The invention relates to ground sweepers of the type used to clean beaches of solid debris and to remove rocks from dirt tracks. In either case the ground contour is irregular and it is difficult to maintain rigid drive units because of the continuing change in attitude between the tractor vehicle and the sweeper itself. In addition the conventional relatively steep pitch of the moving screen of ground sweepers has shortened the effective run of the screen for the purpose of separating large and small solids.
The present invention eliminates rigid drive coupling between the drawing vehicle and the trailing ground sweeper and substitutes sensitive controls for the gross controls of previous tractor-trailer combinations. These advantages are achieved by utilizing hydraulic controls and drives on the trailing vehicle coupled to the drawing vehicle by flexible hydraulic lines connecting to a hydraulic pump driven from the power takeoff unit of the tractor, the pump being fixed to the tractor. Since the conventional tractor has both a hydraulic system and a power takeoff shaft as standard equipment, any tractor of sufficient power can be coupled easily to the ground sweeper of the invention and all of the functions of the sweeper controlled from the driver's seat.